Researchers found that doing both at the same time affects posture and balance, causing people to swerve and walk slower, according to the findings published Jan. 22 in the journal PLoS One.

"Texting, and to a lesser extent reading, on your mobile phone affects your ability to walk and balance. This may impact the safety of people who text and walk at the same time," Siobhan Schabrun, of the University of Queensland in Australia, said in a journal news release.

She and her colleagues looked at the effects of texting while walking in 26 healthy people. Each person was asked to walk a straight line three times: once without a cellphone; once while reading a text on a cellphone; and once while texting on a cellphone.

Texting, and to a lesser degree reading, changed the body's movement while walking. When writing a text, the participants walked slower, swerved more and moved their necks less than when they walked without texting or while reading.

There was also an effect on head movement while texting or reading a text message that could make balance more difficult, the researchers noted.

In addition, texting or reading on a cellphone may create a safety risk for pedestrians while crossing the road or trying to avoid obstacles, the study authors noted.